Question

PILNE! matma ! to proste zadania, ale nie mam czasu nad tym siedzieć ;c

zadania w załącznikach x

prosze o zad 5 i 6 ;))

Answer 1

5.

a)

2(x+1)+3(x-2) < x+4
2x+2+3x-6 < x+4
5x-4 < x+4 /-x
4x-4 < 4 / +4
4x < 8 / :4
x < 2

 

b)

3(x-5)-2(3x-1) > -5x-7
3x-15-6x+2 > -5x-7
-3x-13 > -5x-7 /+ 5x
2x-13 > -7 / + 13
2x > 6 /:2
x > 3

 

c)

(4-3x)-(x-2)-(2x+5) < (2x-1)- (3x-1)
4-3x-x-2-2x-5 < 2x-1-3x-1
4-4x-2-2x-5 < -x-2
1-6x < -x-2 / +6x
1 < 5x-2 / + 2
3 < 5x /:5
3/5 < x

 

d)

(5-x)-(2x-1)+(2x-5) > -(3x-1)-(x-1)
5-x-2x+1+2x-5 > -3x+1-x+1
5-3x+1+2x-5 > -4x
4-x-5 > -4x
9-x > - 4x /+x
9 > -3x / : -3
-3 > x

 

6.

a) (2x+1)/18 + (7-x)/9 = (2x-1)/6      / * 18

     2x+1+14-2x = 6x-3 

15 = 6x - 3 /+3

18 = 6x  /:6

 3 = x

 

b)  (2x-3)/12 + (5-x)/4 = (2x-6)/3   / *12

    2x-3 + 15-3x = 8x - 24 

    2x + 12 - 3x = 8x - 24 

    -x + 12 = 8x - 24 /+ x

    12 = 9x - 24  / + 24

    36 = 9x  / :9

     4=x

 

c)  (x+11)/6 - (-5-2x)/12 = (7+x)/4   / *12

     2x+22+5-2x = 21+3x 

      27 = 21 + 3x / - 21

       6 = 3x / :3

      2=x

 

d) (x+3)/2 - (2x+5)/5 = (1-x)/10     / *10

    5x+15 - 4x+10 = 1-x

    x + 5 = 1 - x / +x

    2x + 5 = 1   /-5

    2x = - 4   /:2

    x = - 2